1. Field of the Invention
The present invention relates to a brushless DC motor arranged with a permanent magnet rotor having a multiplicity of poles magnetized on its outer circumference.
2. Description of the Prior Art
The stator structure of the brushless DC motor is divided into cored and coreless types. The cored type stator is constructed by laminating a number of electromagnetic steel plates punched into a predetermined shape and by winding the slot portion of the stator. For this winding, the slot is insulated on its inner surface and is divided.
The stator of this cored type must have its slot divided before it is wound, therefor its winding works are complicated and raise the production cost.
On the contrary, the coreless stator is advantageous in respect of the winding works but naturally has a worse efficiency in the magnetic circuit because of lack of the core. In order to realize the desired motor performance, therefore, a permanent magnet of high performance is required which raises the production cost.